Enhancing separation of chalcopyrite and molybdenite via ozone micro-nano bubble oxidation and flotation

Chalcopyrite and molybdenite present challenges in flotation separation due to their similar floatability. In this study, ozone micro-nano bubble was employed to oxidize chalcopyrite and molybdenite, altering their surface properties to facilitate them separation via flotation. The flotation results demonstrated a significant reduction in the recovery of chalcopyrite through ozone micro-nano bubble oxidation, while molybdenite remained unaffected. The concentrates with the Mo recovery remained steady at 84 % and Cu recovery below 9 % were achieved in flotation experiments of the artificially mixed ores with various mass ratios of chalcopyrite and molybdenite. Analysis of the results from X-ray photoelectron spectroscopy (XPS), zeta potential, and contact angle measurements indicated that the surface of chalcopyrite was oxidized to form metal oxides and hydroxides after ozone micro-nano bubble oxidation, thereby decreasing its floatability. In contrast, the oxidation products of molybdenite dissolved in the pulp, preserving its original surface and floatability. Additionally, experimental results confirmed that micro-nano bubbles exhibited superior oxidation effectiveness and rate than those of conventional bubbles. In summary, ozone micro-nano bubble oxidation presented a promising green alternative to traditional depressants for the efficient separation of copper and molybdenum sulfide ore.